//
// Created by denglibin on 2021/3/26.
// 使用render渲染，不直接使用surface
#include <SDL.h>
#define WIN_WIDTH 600
#define WIN_HEIGHT 400
#define FRAME_RATE 60 //帧率
#define FONT_SIZE 32
static struct SDL_Window * win; //窗口
static struct SDL_Surface * winSurface; //窗口的surface
static struct SDL_Renderer * winRender;//窗口渲染器


static void draw(){
    //设置渲染器颜色
    SDL_SetRenderDrawColor(winRender, 0, 128, 0, 255);
    SDL_RenderClear(winRender); //用设置的颜色清除

    SDL_SetRenderDrawBlendMode(winRender, SDL_BLENDMODE_BLEND);//设置混合模式，支持alpha透明

    SDL_Rect r = {0, 0, 100, 100};
    //把渲染器设置成红色
    SDL_SetRenderDrawColor(winRender, 255, 0, 0, 128);
    //用矩形填充
    SDL_RenderFillRect(winRender, &r);

    SDL_Rect r2 = {50, 50, 100, 100};
    //把渲染器设置成蓝色
    SDL_SetRenderDrawColor(winRender, 0, 0, 255, 128);
    //用矩形填充
    SDL_RenderFillRect(winRender, &r2);


    //生效
    SDL_RenderPresent(winRender);

}
/**
 * 事件循环
 */
static void eventLoop(){
    SDL_Event  event;
    while (1)
    {//主消息循环
        SDL_PollEvent(&event);
        if(event.type == SDL_QUIT){
            return;
        }
        draw();
        uint32_t  begin = SDL_GetTicks();
        uint32_t  end = SDL_GetTicks();
        uint32_t  cost = end - begin;
        uint32_t per_frame_time = 1000 / FRAME_RATE;//每一帧耗时ms
        if (per_frame_time > cost){
            //减去循环体耗时，得到还应休眠的时间
             SDL_Delay(per_frame_time - cost);
        }
    }

}
/**
 * 初始化操作
 */
static void init(){
    //初始化，成功返回0
    if (SDL_Init(SDL_INIT_VIDEO)) {
        SDL_Log("Can not init video %s\n", SDL_GetError());
        exit(1);
    }
}



/**
 * 创建显示窗口
 * @return
 */
static int showWindow(){

    win = SDL_CreateWindow("Hello World",
                           SDL_WINDOWPOS_CENTERED,
                           SDL_WINDOWPOS_CENTERED,
                           WIN_WIDTH,
                           WIN_HEIGHT,
                           SDL_WINDOW_SHOWN
    );
    if (win == NULL) {
        SDL_Log("Can not create window %s\n", SDL_GetError());
        return 2;
    }

    winRender = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED);
    winSurface = SDL_GetWindowSurface(win);
    return 0;

}

/**
 * 清理
 */
static void clean(){
    SDL_DestroyRenderer(winRender);
    SDL_FreeSurface(winSurface);
    SDL_DestroyWindow(win);
}
int main2_9(int argc, char* argv[]){
    init();
    if (showWindow()){
        exit(1);
    }
    eventLoop();
    clean();
    SDL_Quit();
}

